1 files changed, 123 insertions, 0 deletions
diff --git a/third_party/dav1d/examples/dp_fifo.c b/third_party/dav1d/examples/dp_fifo.c
new file mode 100644
index 0000000000..243d2e933b
--- /dev/null
+++ b/third_party/dav1d/examples/dp_fifo.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright © 2019, VideoLAN and dav1d authors
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <SDL.h>
+#include <assert.h>
+
+#include "dp_fifo.h"
+
+// FIFO structure
+struct dp_fifo
+{
+    SDL_mutex *lock;
+    SDL_cond *cond_change;
+    size_t capacity;
+    size_t count;
+    void **entries;
+};
+
+
+Dav1dPlayPtrFifo *dp_fifo_create(size_t capacity)
+{
+    Dav1dPlayPtrFifo *fifo;
+
+    assert(capacity > 0);
+    if (capacity <= 0)
+        return NULL;
+
+    fifo = malloc(sizeof(*fifo));
+    if (fifo == NULL)
+        return NULL;
+
+    fifo->capacity = capacity;
+    fifo->count = 0;
+
+    fifo->lock = SDL_CreateMutex();
+    if (fifo->lock == NULL) {
+        free(fifo);
+        return NULL;
+    }
+    fifo->cond_change = SDL_CreateCond();
+    if (fifo->cond_change == NULL) {
+        SDL_DestroyMutex(fifo->lock);
+        free(fifo);
+        return NULL;
+    }
+
+    fifo->entries = calloc(capacity, sizeof(void*));
+    if (fifo->entries == NULL) {
+        dp_fifo_destroy(fifo);
+        return NULL;
+    }
+
+    return fifo;
+}
+
+// Destroy FIFO
+void dp_fifo_destroy(Dav1dPlayPtrFifo *fifo)
+{
+    assert(fifo->count == 0);
+    SDL_DestroyMutex(fifo->lock);
+    SDL_DestroyCond(fifo->cond_change);
+    free(fifo->entries);
+    free(fifo);
+}
+
+// Push to FIFO
+void dp_fifo_push(Dav1dPlayPtrFifo *fifo, void *element)
+{
+    SDL_LockMutex(fifo->lock);
+    while (fifo->count == fifo->capacity)
+        SDL_CondWait(fifo->cond_change, fifo->lock);
+    fifo->entries[fifo->count++] = element;
+    if (fifo->count == 1)
+        SDL_CondSignal(fifo->cond_change);
+    SDL_UnlockMutex(fifo->lock);
+}
+
+// Helper that shifts the FIFO array
+static void *dp_fifo_array_shift(void **arr, size_t len)
+{
+    void *shifted_element = arr[0];
+    for (size_t i = 1; i < len; ++i)
+        arr[i-1] = arr[i];
+    return shifted_element;
+}
+
+// Get item from FIFO
+void *dp_fifo_shift(Dav1dPlayPtrFifo *fifo)
+{
+    SDL_LockMutex(fifo->lock);
+    while (fifo->count == 0)
+        SDL_CondWait(fifo->cond_change, fifo->lock);
+    void *res = dp_fifo_array_shift(fifo->entries, fifo->count--);
+    if (fifo->count == fifo->capacity - 1)
+        SDL_CondSignal(fifo->cond_change);
+    SDL_UnlockMutex(fifo->lock);
+    return res;
+}
+
+